The present invention relates to elevator control systems. More specifically, the present invention relates to controlling the distance between a leading elevator car and a trailing elevator car traveling in the same direction in an elevator hoistway.
An objective in elevator system design is to minimize the required number of elevator hoistways that are employed within the elevator system, while also trying to effectively meet the transportation needs of passengers and freight within the building. Solutions aimed at reducing the number of hoistways and improving service have included higher elevator travel speeds, shorter door opening and closing times, advanced control systems, express elevators, splitting buildings into zones, and so on. However, in buildings having a large number of stories, these measures may result in a feeling of unease when elevators accelerate, inconvenience when doors quickly close, or frustration as a result of using a complicated system, where passengers may have to change between elevator cars one or more times to get to a desired floor.
One approach to increasing the efficiency of passenger transport while minimizing the number of elevator hoistways is to incorporate multiple independently controllable elevator cars into each hoistway that are each capable of servicing most or all of the floors in the building. In such a system, each elevator car must be separated from the others by a certain distance for safe operation of the elevator cars. When two or more elevator cars are traveling in the same direction in the hoistway, the timing of the runs assigned to the elevator cars becomes important with respect to anticipated and unanticipated stops to avoid interference between the elevator cars.
In light of the foregoing, the present invention aims to resolve the need to ensure a sufficient and proper separation distance between elevator cars traveling in the same direction in a hoistway.